6e2efe3aa4
Major difference is that I removed Deref impls, as apparently LLVM has trouble maintaining metadata with a `&ptr -> &ptr` API. This was cited as a blocker for ever stabilizing this API. It wasn't that ergonomic anyway. * Added `get` to NonZero to replace Deref impl * Added `as_ptr` to Shared/Unique to replace Deref impl * Added Unique's `as_ref` and `as_mut` conveniences to Shared * Added `::empty()` convenience constructor for Unique/Shared * Deprecated `as_mut_ptr` on Shared in favour of `as_ptr` * Improved documentation of types Note that Shared now only refers to *mut, and not *const
56 lines
1.9 KiB
Rust
56 lines
1.9 KiB
Rust
// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
|
|
// file at the top-level directory of this distribution and at
|
|
// http://rust-lang.org/COPYRIGHT.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
|
|
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
|
|
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
|
|
// option. This file may not be copied, modified, or distributed
|
|
// except according to those terms.
|
|
|
|
//! Exposes the NonZero lang item which provides optimization hints.
|
|
#![unstable(feature = "nonzero",
|
|
reason = "needs an RFC to flesh out the design",
|
|
issue = "27730")]
|
|
|
|
use ops::CoerceUnsized;
|
|
|
|
/// Unsafe trait to indicate what types are usable with the NonZero struct
|
|
pub unsafe trait Zeroable {}
|
|
|
|
unsafe impl<T:?Sized> Zeroable for *const T {}
|
|
unsafe impl<T:?Sized> Zeroable for *mut T {}
|
|
unsafe impl Zeroable for isize {}
|
|
unsafe impl Zeroable for usize {}
|
|
unsafe impl Zeroable for i8 {}
|
|
unsafe impl Zeroable for u8 {}
|
|
unsafe impl Zeroable for i16 {}
|
|
unsafe impl Zeroable for u16 {}
|
|
unsafe impl Zeroable for i32 {}
|
|
unsafe impl Zeroable for u32 {}
|
|
unsafe impl Zeroable for i64 {}
|
|
unsafe impl Zeroable for u64 {}
|
|
unsafe impl Zeroable for i128 {}
|
|
unsafe impl Zeroable for u128 {}
|
|
|
|
/// A wrapper type for raw pointers and integers that will never be
|
|
/// NULL or 0 that might allow certain optimizations.
|
|
#[lang = "non_zero"]
|
|
#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Debug, Hash)]
|
|
pub struct NonZero<T: Zeroable>(T);
|
|
|
|
impl<T: Zeroable> NonZero<T> {
|
|
/// Creates an instance of NonZero with the provided value.
|
|
/// You must indeed ensure that the value is actually "non-zero".
|
|
#[inline(always)]
|
|
pub const unsafe fn new(inner: T) -> NonZero<T> {
|
|
NonZero(inner)
|
|
}
|
|
|
|
/// Gets the inner value.
|
|
pub fn get(self) -> T {
|
|
self.0
|
|
}
|
|
}
|
|
|
|
impl<T: Zeroable+CoerceUnsized<U>, U: Zeroable> CoerceUnsized<NonZero<U>> for NonZero<T> {}
|